An LED is a solid semiconductor device capable of converting electric energy to visible light. LED lighting devices are considered energy-saving, environmentally friendly, and light controllable. The LED lighting devices may have high practicability, high stability, short response time, and long service time. LED lighting devices have been widely used in various lighting applications in accordance with a low-carbon life style.
External power grids are often used to provide electricity to LED lighting devices for emitting light. When external power grids malfunction or have power outages, the LED lighting devices will not work and would not be able to provide lighting for users. Users would have to use flashlights or other lighting devices for temporary lighting.
However, other lighting devices for emergency use do not have ideal lighting performances and require a manual operation, which may be time consuming and may cause inconvenience. Unpredictable risks may occur. In addition, when LED lighting devices are operating properly, the temporary lighting device for emergency conditions are not in use. Resources may be wasted.
The disclosed circuit and device are directed to solve one or more problems set forth above and other problems.